Internet Explorer looking for token for unsecured service

We have an application that uses a javascript page to display a map with layers from and unsecured GIS service on our GIS server. Last week, the page stopped working on our internal network in Internet explorer. When I attempted to run the application through visual studio, the page errors out with an error saying "Access Denied" where it looks like the javascript is trying to obtain a token from the GIS server. Anyone know why this would be doing this on an unsecured service? And why it would occur with no changes to the code? We have the application on a public site as well, there are no issues there.